Yarn-treating apparatus



c. L. LOVELAND ETAL 2,994,938

YARN-TREATING APPARATUS Filed June so, 1959 INVENTORS CHESTER L.LOVELAND PACIFIC J. THOMAS ATTORNEY United States Patent 2,994,938YARN-TREATING APPARATUS Chester L. Loveland, Dalton, and Pacific J.Thomas,

Wyoming, Pa., assignors, by mesne assignments, to E. I. du Pont deNemours and Company, Wilmington, Del., a corporation of Delaware FiledJune 30, 1959, Ser. No. 824,024

. 4 Claims. (Cl. 28'1) This invention relates to a process and apparatusfor treating a bundle'of filaments such as a yarn to produce a bulkystrand composed of a plurality of individually crimpcd filaments.

Artificial fibers are normally produced most easily as continuousfilaments. These continuous filament yarns are very strong because ofthe absence of loose ends that are unable to transmit imposed stresses.Their extreme uniformity and lack of discontinuity, however, makesconventional continuous filament yarns much more dense than yarns madefrom staple fibers. The production of yarn from staple fibers, however,is time-consuming and requires a complex series of operations to crimpthe fibers, align the fibers into an elongated bundle and then to drawthe bundle to successively smaller diameters. The final spinningoperation, which involves a high degree of twist, finally binds thesediscontinuous fibers together to produce a coherent yarn withconsiderably increased bulk. The occluded air spaces give them alightness. covering power, and warmth-giving bulk not normally possiblewith continuous filament yarns. Thus, to get staple fibers that can beprocessed on conventional wool or cotton spinning equipment, it has beenthe practice to cut continuous filament yarns such as rayon, acetate,nylon, as well as the polyacrylic and polyester fibers into shortlengths for spinning into staple yarn.

Recent developments in the textile industry have provided useful routesfor improving the bulk and covering power and recoverable elongation ofcontinuous filament yarns without resorting to the staple spinningsystems of the prior art. A well-known process for making stretch yarninvolves the steps of twisting, heat-setting and then backtwisting to alow final twist level. Another yarn of improved bulk is preparedcommercially by the steps of twisting, heat-setting and backtwistingon-the-run using a false-twisting apparatus. This end product can befurther modified by hot relaxing to improve the bulk and bandle. Stillanother bulk yarn is being prepared by the well-known stuffer boxtechnique wherein the yarn is steamed to heat-set while it is in acompressed state in the stufier box.

All of these yarns of the prior art are produced by a process which hasthe common elements of deforming the yarn mechanically and thenheat-setting either with or without an after-relaxation step. It was notuntil the recently disclosed product in US. 2,783,609 to Breen and itsprocess of manufacture became known that an entirely new techniquebecame available for improving the bulk of continuous filament yarns.This technique involves exposing a filamentary material to a rapidlymoving turbulent fiuid, thereby inducing a multitude of crunodalfilament loops at random intervals along the individual filaments. Theseloops and snarls of entangled loops increase the bulk of the continuousfilament yarns considerably and result in fabrics of improved cover,bulk, handle, and the like. With the invention of Breen, a new tool isavailable for the bulking of filamentary structures, i.e., a turbulentfluid. Fluids, of course, have been used for yarn treating in many ofthe prior art operations such as drying, extracting, transporting, andthe like. Until the invention of Breen, however, they had not been usedto entangle, convolute, and bulk a filamentary ma terial. It has nowbeen discovered, however, that a new Z..,ti4,il38 Patented Aug". 8, 1961apparatus for utilizing the turbulent fiuid technique results in newyarn products that have certain unique properties, particularly withrespect to the uniformity of the yarn products produced and thereproducibility of those products from one machine to another.

It is an object of the present invention to provide a new apparatus forproducing bulky yarns of the type and in accordance with the generalprocess disclosed in US. 2,783,609 and US. 2,869,967 to Breen. Anotherobject is to provide an apparatus for producing substantially moreuniform bulky yarns than has been possible with known apparatus usingthe fluid jet technique of the Breen patent. The apparatus of thisinvention will be more readily understood by reference to the drawingwhich represents a sectional view of a preferred embodiment of thefluid-treating apparatus of this invention.

In the apparatus shown in the drawing. the housing 1, pierced lengthwiseby cylindrical channel 2, which in this embodiment is restricted at oneend to form neck 3, contains needle 4 which is also cylindrical in crosssection. Needle 4 is pierced by an axial cylindrical channel 5 having aflared mouth 6 for introducing yarn into the ap paratus. The cylindricalbody 7 of needle 4, which preferably has an exterior diameter of 0.187inch and a length of 0.6 inch, is smaller in cross section than channel2, which preferably has an interior diameter of 0.42 inch, therebyforming a right cylindrical annular plenum chamber 8 which surrounds theneedle body 7 within the apparatus and this plenum chamber is suppliedwith compressible fiuid, preferably air, through lateral conduit 9 froma source of air not shown. The tip of the needle preferably has a lengthof 0.41 inch and is tapered in this embodiment from the body 7 at itsinner extremity 11 toward the fiat inner end of the needle 10, whichpreferably has a diameter of 0.066 inch, by means of two right conicalshoulders 13 and 14, Where the corresponding cones have vertex anglesbetween about 30 and about 120, separated by a right cylindrical section15 which preferably has an exterior diameter of 0.140 inch and a lengthof 0.28 inch. These right conical shoulders preferably will be 0.066inch in height and have the same slope, an angle of 60 being preferred,but shoulder 14 may have a slope (apex angle at the vertex of thecorresponding cone) less than that of shoulder 13 but equal in degreesto at least of the apex angle of shoulder 13. The width of the annulussurrounding the tip of the needle (the difference between the outsideand inside diameters of a cross section of the annulus) should besubstantially the same throughout the length of the needle tip, that is,from point 11 where the tip of the needle meets body 7 to the fiat innerend ll) of the needle. (ylindrical annulus 8 sun-minding the body of theneedle within the apparatus should be at least as wide (differencebetween minimum and maximum diameters) as the annulus surrounding thetip of the needle and desirably will be somewhat larger in order toinsure smooth operations and adequate air velocity for crimping yarn.

Removably inserted in the opposite end of cylindrical chamber 2 awayfrom needle 4 is orifice block 16 closely fitted into housing 1 toprevent air leakage. Orifice block 16 is longitudinally adjustablewithin channel 2 and is perforated by an axial cylindrical yarn outlet17. the inner end 18 of which coincides with the smaller end of thetapered annular channel within the appurtus. The inner end of this yarnoutlet is spaced from and concentric with the yurn passageway 5 inneedle 4 and is larger in cross-sectional area than yarn inlet 5. Yarninlet 5 may be uniformly cylindrical throughout but preferably will havea nozzle 24 of reduced cross-sectional area at the inner end of theneedle at shoulder 14 to maintain friction on yarn passing through theneedle at a minimum. The conduit 17 terminates inside the apneedle beingin the form of two conical sections 19 and 20 separated by anintermediate cylindrical section 21 and preferably exceeding thecross-sectional diameter of the yarn needle at each point along itslength by about 0.08 inch, so that when the apparatus is fully assembledas shown in the drawing the tip of the needle is surrounded by atapering annular plenum chamber 22 of substantially uniform widththroughout and formed by the spaced apart conical sections andintermediate cylindrical sections of the needle tip'and the surroundingorifice block mouth, respectively.

Preparatory to operation, the orifice block 16 is adjustedlongitudinally within the housing to provide for the smoothestthroughput of air or other compressible fluid and no further adjustmentis necessary. Needle 4 is fixed within the housing during manufacture inorder that it may be centered precisely in the center of cylindricalchamber 2 and require no further adjustment. Since there is only asingle simple adjustment to be made in Operating the apparatus,uniformity of processing from one machine or one plant location toanother and from one operator to another can be maintained within veryclose limits permitting the production of uniform yarn products with avery minimum of control and without the need for highly skilledoperators.

in operation. air is forced into annular chamber 8 within the housing 1by way of lateral conduit 9, whence it passes through tapered annulus 22to the tip of needle 4 while at the same time increasing in velocity dueto its increasing confinement along this path. A zone of turbulence 23is created between the flat end 10 of the needle and the inner end 18 ofyarn outlet 17 as the fluid rushes into this area from all sections ofthe conical annulus, thence passing to the exterior of the apparatusthrough conduit 17. Yarn is fed into zone of turbulence 23 from yarntube where it is agitated violently and whipped about and removed viaconduit 17 along with the high velocity air. The yarn is removed fromthe air stream immediately upon issuing from conduit 17 by withdrawingit to one side. It is important that the apparatus have dimensions suchthat air or other compressible fluid utilized will have a velocity equalto at least V2 sonic velocity and preferably sonic velocity where itfirst strikes the yarn in the zone of turbulence 23 and that thecross-sectional area of the outlet conduit 17 be of sufficient size tomaintain back-pressure in the yarn inlet 5 at a minimum withoutdecreasing yarn velocity in the zone of turbulence substantially.

The apparatus of this invention is especially suitable for carrying outthe bulking process disclosed in US. 2,783,609 and US. 2,869,967 toBreen, but is particularly useful for treatment of glass yarns or forthesimultaneous treatment or combining of two or more yarn ends to providecomposite yarn products having special aesthetic characteristics inaddition to high bulk. It is one of the important and surprisingattributes of the apparatus of this invention that more uniform bulkyyarn products both of synthetic filaments and glass filaments can bemade than was possible heretofore.

Another advantageous characteristic of the apparatus of this inventionis the fact that it permits difierent operators to produce bulky yarnproducts having the same highly uniform characteristics. This arisesbecause the jet has only one adjustment and this can be regulated solelyupon the effective throughput of air. In prior known fluid treatmentapparatus several adjustments were usually possible and necessary andcould only be made by a skilled operator after examination of yarnproducts produced and an evaluation of the quality and uniformity of thebulk and other characteristics of that product. Because no twooperators, however skilled, evaluated yarn product characteristicsexactly alike and because the fluid treating apparatus was notsusceptible to precise adjustmerit, quality of bulky yarn products withprior art apparatus varied substantially from operator to operator. frommachine to machine, and from one plant location to another. Theapparatus of the present invention remedies that situation.

The absolute and relative dimensions of the yarn inlet tube 5 and theoutlet conduit 17 may be varied fairly widely but outlet tube 17 must bethe larger. One advantageous attribute of the apparatus of thisinvention is the effectiveness in processing a great variety of yarncounts without necessity of a change in the dimensions. For example,with a yarn inlet tube diameter of 0.028 inch, yarns varying in denierfrom about 80 to 1300 or more may be readily processed using an outlettube diameter of 0.056 inch. An inlet tube diameter of 0.040 inch withan outlet tube diameter of 0.070 inch is suitable for processing yarnsvarying in denier from about 1000 to 5000 and is especially good forprocessing glass fiber yarns or mixing two or more synthetic organicfilament yarns. Generally, the needle end 10 is spaced from outlet tubeend 18 by a distance of about 0.008 inch to 0.020 inch. Thecharacteristics of the yarn product usually suffer if these latterlimits are exceeded. The width of the conical annulus 22 surrounding thetip of the needle is desirably uniform throughout and an annulus havinga minimum diameter of inch and a maximum diameter of inch is suitablefor processing most yarns as providing an air velocity in the zone ofturbulence 23 of at least /2 sonic and sometimes supersonic dependingupon the other characteristics of the apparatus. thereby making the yarnbulking procedure exceedingly efficient from the standpoint of economyof air consumption and yarn throughput while at the same time producingan unusually uniform product both from the standpoint of the size of theloops and whorls in the bulky yarn product and their uniform dispositionthroughout the bulky yarn.

Of course, a particular fluid treating apparatus having certain selectedinterior dimensions may be chosen for its peculiar effectiveness with acertain yarn and its economy of air consumption, manufacturing expense,or other factors. Apparatus employing the principles of the presentinvention but differing somewhat in configuration will be obvious tothose skilled in the art. In one such variation, for example, theannulus 22 shown in the drawing comprising the two annular conicalsections separated by a cylindrical annulus may be replaced by twocontiguous annular conical sections, thereby eliminating thecylindrica-l annulus. Similarly, a device having three contiguousannular conical sections about the tip of the needle or any number ofsuch conical annular sections with a cylindrical annulus intermediateadjacent sections would also be feasible although much more difiicult tomanufacture. The apparatus shown in the drawing is particularlypreferred in this invention because a more highly uniform bulky productis attained under normal operating conditions with high throughput ofyarn and efficient consumption of air than with other apparatuses ofthis type.

The process and apparatus of this invention can be used to crimp andbulk any natural or synthetic filamentary material. Certainthermoplastic materials such as polyamides, e.g., poly(epsiloncaproamide), poly(hexamethylene adipamide); cellulose esters;polyesters, c.g., polyethylene terephthalate, poly(hexahydro-p-xylyleneter ephthalate), etc.; polyvinyls and polyacrylics, e.g., polyethyleneand polyacrylonitrile, as well as copolymers thereof, are particularlysuitable for producing the uniformly bulked products described herein.While the preferred form of material is continuous filaments, theprocess and resultant improvements occur with staple yarns as well. Bothtypes of materials can be made into bulky yarns and fabrics havingimproved bulk, covering power (opacity) and hand.

This apparatus and process are useful for both monofilament yarns intextile deniers as well as the heavier ill.

carpet and industrial yarn sizes either singly or combined in the formof a heavy tow. Fine count and heavy count staple yarns can be processedboth singles and plied. The process and product are also not restrictedin the case of the synthetic materials to any one particular type offilament cross section. Cruciform, Y-shaped, delta-shaped, ribbon, anddumbbell and other such filamentary cross sections can be processed atleast as well as round filaments and usually contribute still more bulkthan is ob tained with round filaments. By proper design of the jet andprocess, multiple ends of yarn may be handled either in the form of warpsheets, ribbons, or tows.

In using the apparatus of this invention yarn is fed into the yarn inlettube at an overfeed which will depend upon the character of the feedyarn as well as the particular characteristics desired in the product.When the apparatus is used to combine and bulk two or more yarns, one orboth of them may be fed into the apparatus with overieed and, if bothare fed with overfeed, the overfeed with one yarn may be the same ordifferent from that applied to the other. Overfeeds as high as 400% havebeen utilized effectively.

Although the invention has been illustrated with air, steam or any othercompressible fluid or vapor may be utilized. Air is particularlypreferred because of its cheapness and convenience.

The configuration and accompanying characteristics of the yarn producedby the apparatus of this invention depend in part upon the amount andvelocity of the air characteristics of the apparatus, yarn speed, andthe yarn fibers being treated. For optimum bulking the apparatusperimeters must be carefully determined. The size of the yarn inlet 5 aswell as that of the yarn outlet 17 depends upon the type and denier ofthe yarn being processed. The yarn inlet 5 should be just large enoughto allow passage of the yarn with a minimum of drag due to friction andyet be small enough to minimize the flow of air back through this yarninlet from the plenum chamber. The outlet tube 17 must be large enoughto allow the crimped yarn to exit along with the treating air withoutimposing excess tension on the yarn bundle and without reducingsubstantially the metering action of the conical annular plenum chambersurrounding the tip of the needle.

The eflicient bulking action of this apparatus apparently results fromthe action of high velocity fluid on the individual yarn filaments asthe yarn passes through the zone of turbulence at the tip of the yarninlet needle. It appears that the yarn is opened up due to the action ofthe fluid in the zone of turbulence and that the individual filamentswithin the yarn bundle are separately whipped about and randomly twistedso that they become intimately entangled and interlocked with adjacentfilaments while at the same time being formed into loops and whorlsuniformly through the yarn bundle to provide the desired bulking action.Apparently also, a fluid vortex is formed so that in addition to theloopy characteristics in the yarn product and the individual twist,intermingling and interlocking of fibers within the yarn bundle, theyarn bundle itself assumes an alternate twist configuration whichremains in the yarn after it is removed from the appastatus. Quitepossibly it is the interlocking and intermingling of the yarn fiberswithin the bundle which make this apparatus particularly suitable forbulking fiber glass yarns because processing such a fiber glass yarnproduces a compact yarn bundle which is coherent and further processablein the same manner as a unitary strand. Prior art fluid treatingapparatuses for bulking yarns have been ineffective for the treatment offiber glass yarns since the resulting product was usually neithercoherent nor unitary. Because of the unifying results produced by theapparatus of this invention, the feed yarn may be twisted or untwistedand quite obviously the product may be twisted or not, as desired. Wherea zero twist yarn is fed to the apparatus, the product is a bulked yarnin which the filaments are intermingled and interlocked with one anotherbesides being uniformly loopy throughout 6 and there is no need to twistthis product for further processing.

Example I Using the fluid treating apparatus shown in the drawing havinga yarn inlet diameter of 0.028 inch and a yarn outlet diameter of 0.056inch. three fiber glass yarns (150 l/0lZ) were fed into the jet at arate of 34 yards per minute and another fiber glass yarn (150 l/OlZ) wassimultaneously fed into the jet at 70 yards per minute. Air pressuresupplied to the jet was 60 p.s.i.g. The bulked composite yarn leavingthe jet was wound up at 30 yards per minute, being withdrawn from theair stream issuing from the jet at the jet exit. The yarn product wa aboucl.

Example II Using the jet of Example 1, three strands of fiber glass yarn(150 l/OlZ) were fed into the jet at yards per minute and wound up at 90yards per minute. Air pressure supplied to the jet was 70 p.s.i.g. Thisyarn was also a boucl.

Example 111 Two yarns, one a l50-400 blue acetate yarn and the other a150-40-0 red acetate yarn, were fed into the jet of Example Isimultaneously at the rate of 50 yards per minute and wound up at 41yards per minute Air pressure supplied to the jet was 40 p.s.i.g. Theyarn product was a homogeneous mixture of the bulked blue and redacetate yarns and having a uniform bulk throughout due to the uniformdisposition of loops and whorls throughout the yarn product bundle.

Example IV A l406Sl/2Z nylon yarn was fed into the jet of Example I at35 yards per minute and two effect yarns. one a 3300-80-52 blue acetateyarn and the other a l00- 80-52 blue acetate yarn, were fed into the jetsimultaneously with the nylon yarn at the rate of 130 yards per minute.The bulked product was removed from the jet and wound up at 31 yards perminute. Air pressure supplied to the jet was 50 p.s.i.g. The product wasa chenille-type yarn having a nylon core and an acetate effectcomponent.

We claim:

1. A yarn-treating apparatus comprising a housing perforated by acylindrical channel, a yarn needle of circular cross section having anaxial yarn passageway for introducing yarn into the apparatus, saidneedle being p0- sitioned in and concentric with the cylindrical housingchannel and closely fitted into one end of the housing channel andcomprising a cylindrical body portion and an inner tapered tip portion,both within the housing channel, the body portion being substantiallysmaller in cross section than the housing channel to provide an annularplenum chamber, the tip portion extending from the body portion to afiat inner end of the yarn needle and diminishing in cross sectiontoward the inner end in at least one graduated step in the form of acylindrical section separated from the flat inner end and the bodyportion of the yarn needle, respectively, by shoulders. each in the formof a right conical section having a vertex angle between about 30 andabout the vertex angle of the shoulder adjacent the inner end being utleast 75% of the Vertex angle of the shoulder adjacent the needle body;a cylindrical orifice block closely fitted into the opposite end of thehousing channel from the yarn needle and longitudinally adjustablewithin said channel, said orifice block being perforated by an axialyarn outlet spaced from and in-line with the yarn passageway, saidoutlet being circular in cross section throughout and tubular at itsouter end, but widened at its inner Cllti to form n mouth-sectionsurrounding the tip portion of the yarn needle and having a geometrycomplementary to that of the tip of the yarn needle but of substantiallylarger cross-sectional area, thereby forming the outer walls of anannular chamber about said tip, which annular chamher diminishes indiameter in the direction of the tip of the needle in the same step-wisemanner as the diameter of the needle tip diminishes in size; an airconduit for introducing air into the annular chamber surrounding thebody of the needle.

2. A yarn-treating apparatus comprising a housing perforated by acylindrical channel and having the following relative dimensions, a yarnneedle of circular cross section having an axial cylindrical yarn inletwith a nozzle diameter of 0.028 to 0.040 inch for introducing yarn intothe apparatus, said needle being positionedin and concentric with thecylindrical housing channel and closely fitted into one end of thishousing channel and comprising a cylindrical body portion with anexterior diameter of 0.187 inch and a length of 0.6 inch and an innertapered tip portion having a length of 0.41 inch, both within thehousing channel. the housing channel having an interior diameter of 0.42inch to provide an annular plenum chamher about the needle body, the tipportion of the needle extending from the body portion to a fiat innerend of the yarn needle having a diameter of 0.066 inch with the yarnneedle diminishing in cross section from the needle body toward theinner end in at least one graduated step in the form of a cylindricalsection 0.140 inch in diameter and 0.28 inch long, which cylindricalsection is separated from the fiat inner end and the body portion of theyarn needle, respectively, by shoulders each in the form of a lightconical section 0.066 inch in height and having a vertex angle of 60; acylindrical orifice block closely fitted into the opposite end of thehousing channel from the yarn needle and longitudinally adjustablewithin said needle, said orifice block being pierced by an axial yarnoutlet in-line with the yarn passageway and spaced from the end of theyarn needle 2 distance between about 0.008 inch and about 0.020 inch,said outlet being circular in cross section throughout and cylindricalat its outer end with a diameter of 0.056 to 0.070 inch but widened atits inner I end to form a mouth-section surrounding the tip portion ofthe yarn needle and having a geometry complementary to that of the tipof the yarn needle but exceeding the cross-sectional diameter of theyarn needle at each point along its length by about 0.08 inch, therebyforming the outer walls of an annular stepwise tapered chamber aboutsaid needle tip, which annular chamber diminishes in diameter in thedirection of the tip of the needle in the same step-wise manner as thediameter of the needle diminishes in size; an air conduit for intIo-.ducing air into the annular chamber surrounding the body of the needle.

3. The yarn-treating apparatus of claim 2 in which the yarn inletdiameter is 0.040 inch and the yarn outlet diameter is 0.070 inch.

4. The yarn-treating apparatus of claim 2 in which the yarn inletdiameter is 0.02.8 inch and the yarn outlet diameter is 0.056 inch.

References Cited in the tile of this patent Great Britain Apr. 2, 1959

